บทที่ 2 Semiconductor and P-N junction EEE270 Electronic engineering

Semiconductor material Silicon wafer EEE270 Electronic engineering

Semiconductor material Silicon crystal Sand 25% silicon EEE270 Electronic engineering

Semiconductor material EEE270 Electronic engineering

EEE270 Electronic engineering Silicon atom EEE270 Electronic engineering

Intrinsic semiconductor Silicon Crystal at T= 0 °K EEE270 Electronic engineering

EEE270 Electronic engineering Energy gap EEE270 Electronic engineering

EEE270 Electronic engineering Energy level An electron-volt is the energy of an electron that has been accelerated through a potential difference of 1 volt, and 1eV= 1.6*10-19 joules EEE270 Electronic engineering

Intrinsic semiconductor Silicon Crystal at T > 0 °K EEE270 Electronic engineering

The Intrinsic Carrier Concentration ni is the intrinsic carrier concentration B is a constant related to the specific semiconductor material Eg is the band-gap energy (eV) T is the temperature (°K) k is Boltzmann’s constant (86 x 10-6eV/°K) EEE270 Electronic engineering

Electrical current EEE270 Electronic engineering

Doping and Extrinsic Semiconductors EEE270 Electronic engineering

Basic silicon doping ขั้นตอนในการแพร่สารเจือเบื้องต้น หลักการแพร่กระจายของหมึกในนํ้า แสดงการแพร่สารเจือ (Diffusion) เกิดเป็นรอยต่อ P-N EEE270 Electronic engineering

Type of doping process เตาแพร่สารเจือที่มีแหล่งจ่ายเป็นของแข็ง เตาแพร่สารเจือที่มีแหล่งจ่ายเป็นของเหลว เตาแพร่สารเจือที่มีแหล่งจ่ายเป็นแก๊ส การโดปโดยใช้วิธียิงอิออน (Ion-Implantation) EEE270 Electronic engineering

N-type semiconductor EEE270 Electronic engineering

EEE270 Electronic engineering P-type semiconductor EEE270 Electronic engineering

Thermal equilibrium no = thermal equilibrium concentration of free electron po = thermal equilibrium concentration of hole Silicon Crystal at T > 0 °K EEE270 Electronic engineering

Thermal equilibrium (N-type) EEE270 Electronic engineering

Thermal equilibrium (P-type) EEE270 Electronic engineering

Drift and Diffusion Currents EEE270 Electronic engineering

Drift and Diffusion Currents EEE270 Electronic engineering

Drift and Diffusion Currents EEE270 Electronic engineering

Drift and Diffusion Currents EEE270 Electronic engineering

Drift and Diffusion Currents EEE270 Electronic engineering

Drift and Diffusion Currents EEE270 Electronic engineering

Drift and Diffusion Currents EEE270 Electronic engineering

Drift and Diffusion Currents EEE270 Electronic engineering

P-N junction Bell Labs the first transistor in December 1947. EEE270 Electronic engineering

P-N Junction EEE270 Electronic engineering

The Equilibrium P-N Junction EEE270 Electronic engineering

The Equilibrium P-N Junction Barrier potential or Built-in voltage is called thermal voltage, approximately 0.026V at room temperature, T=300 °K EEE270 Electronic engineering

Built-in voltage EEE270 Electronic engineering

P-N Junction biasing Forward-bias Non-bias Reward-bias EEE270 Electronic engineering

P-N Junction biasing EEE270 Electronic engineering

Junction capacitance EEE270 Electronic engineering

Reverse-Biased P-N Junction Reward-bias Cj : Junction Capacitance Cj0 : Junction Capacitance at zero applied voltage VR : Reverse bias voltage Vbi : built-in voltage EEE270 Electronic engineering

Forward-Biased P-N Junction IS : Reverse-bias Saturation current, in the range of 10-15 to 10-13 VT : Thermal voltage n : emission coefficient or ideality factor, in the range 1  n  2 EEE270 Electronic engineering

Forward-Biased P-N Junction EEE270 Electronic engineering